Manufacturing a printhead that has relatively high resolution and print-speed raises a number of problems.
Difficulties in manufacturing pagewidth printheads of any substantial size arise due to the relatively small dimensions of standard silicon wafers that are used in printhead (or printhead module) manufacture. For example, if it is desired to make an 8 inch wide pagewidth printhead, only one such printhead can be laid out on a standard 8-inch wafer, since such wafers are circular in plan. Manufacturing a pagewidth printhead from two or more smaller modules can reduce this limitation to some extent, but raises other problems related to providing a joint between adjacent printhead modules that is precise enough to avoid visible artefacts (which would typically take the form of noticeable lines) when the printhead is used. The problem is exacerbated in relatively high-resolution applications because of the tight tolerances dictated by the small spacing between nozzles.
The quality of a joint region between adjacent printhead modules relies on factors including a precision with which the abutting ends of each module can be manufactured, the accuracy with which they can be aligned when assembled into a single printhead, and other more practical factors such as management of ink channels behind the nozzles. It will be appreciated that the difficulties include relative vertical displacement of the printhead modules with respect to each other.
Whilst some of these issues may be dealt with by careful design and manufacture, the level of precision required renders it relatively expensive to manufacture printheads within the required tolerances. The applicant has designed a printhead module having a dropped row that addresses at least some of these issues. It would be desirable to provide a printer controller capable of supplying data to such a printhead module.